SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '0c83e8757adfc04464be6ee7e6953080d21c13910b899d31ad181d022d997e45' 
  AND token = '16z7/sO0Ps/nBFQ3XyQN4jVr6Ae7NqAYsQPgDtLSzWs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00051

JSON explain

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