SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '754471f2610f0b90ee8119e222c89750cd95a36b3f6455cbc347b61e9234114a' 
  AND token = 'XuG7J/XipAUxzF+Coj7KOtxJxjvwIr2hHyp0u3TPAvg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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