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SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '5b0e72b18902242cebf5ec9d7a640d16ba8d57b68010a2c767afa52cc027de77' 
  AND token = 'wric7W9uNxVh2tHx5r/9lc24rdtNg2/0JN2qqTQ4ANM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}