SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'de3aec4169d44217347f6d1ab623b4714ff5cf5757404893efc6639eb183b949' 
  AND token = '0P+QO5JM5zbMZZd7aoxstrjI+qguBK0fkDiQGu5Qfm4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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