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SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'c71e82d979bdcc4ad96b3043409f99e2e2548bd0ece7c953ef76fe09b4b7408f' 
  AND token = 's5Dc2w0GDE94NVOLLej0pD2UzQAPrvRXcoacR9zD+rE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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