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SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'b86d6e2fc945a7c4f985ae9e458c8ca222ce2c9b498f8276dc1a679f831209b1' 
  AND token = 'JbEfAGKhFVGrDKPfG8zO9SnkKbroQWY5FbxWoF8BM9g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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