SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'd3a3fe251f329ae15a5d81f4626a672a58820cd442405910748708ba8be7f6f3' 
  AND token = 'scEWZ2iC7ah3rCZshldskinBj4c35Rdi9W49pd76F0Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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