SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'dbbfc55038f2d0bc63824ddb7598d80794e7721fcc8cf4f7f6674910b78f7f82' 
  AND token = 'iQaYCgCQXGXgAsjWrwwYxVhkFEbowPjjwwFHiKTB9jM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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