SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f1d54268638419301023fa25ae55c20198feebf37d4cab0167626c97ff38cc69' 
  AND token = 't/IXXPGdqFiA0BYd2q26ghSRI8HywsmyrjzmqRX81lA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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