SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '345207d3bf9ec7c906823b4e6807e3997946f9aca1dc40a297d049e2c504c35c' 
  AND token = 'r7Cw6hsv+DDFR8Vo1gFIEstCYKs8gjZsfklXnTjI17E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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