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SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '828a45732ef7bda30bafb8c458d4b5357cf1fc735016db506d4188860455c945' 
  AND token = 'S2xqrBlqzl95apbofx2FyCSLfu3Zc3ASom6qytWtGO0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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