SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f4d21a45b9931fb7c3bdbf746d85715f162b83a1fe31f30bda7afa2ffc414567' 
  AND token = 'Uoebk0IVYFdwmFgB3fnDkDSgm4xmQiHKfZzoePtN3Vk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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