SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '2df85cca48440423b6015fc2a60be601b3c51b80dcdf3853982f7ea7e84ca297' 
  AND token = 'O+NxMU8QAnR7aQTDRIDZI8izpngdDrl9zmHsa+mr+co=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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