SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '42d00674e3f5652d0f6b4b2f49ba9c098679b168e0cb2cb1946e65b5c3130caf' 
  AND token = 'vzKjL8/SpbuezVnYP0JUFr9ekVZxcGFXQR8g75dWOHA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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