SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f1e83d9474a561647b5a82add7cdea7ff69e739fd314368b329f1a5b86ac5602' 
  AND token = 'tVUJdHRoV60VjYIKA3kQPQW7nyE/vC6B1WuN4R9hGTg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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