SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f3699464182e14d618c7e6e9c3ad002df72bbd9f191d2ebe2aedef5fa5fcbb2a' 
  AND token = 'cj7BTQi8o1OMlgTR//QtyybRWWigkO/BtyYAcMJAJ7c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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