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SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '39ef9d0727ccc3cb9a3cf29d3cb2be87c5772c7cb047e93a1612ab3b5a1e9fe3' 
  AND token = 'tCo8cdmNy/ryurdMm85p0vXMb81kYDNKFkCi+9b8+Jg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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