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SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '5c6c7aa90378d1c9ab8344411d6d62429be3eeeade85b254ee7f5cd65f14aa48' 
  AND token = 'v+EqZOLl2575+pcTfMVyzMeTuKjs/Jty/V38ZaMD8V4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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