SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '9f3ea2d0b59517d0403c4c2aa8971d312e3b74c9a1bb2ae4fb8890c17e671693' 
  AND token = 'oPmjLUeCSSDHkzCQ3McQ7BcGHyvcPK+ngHnZZS/2OUY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00051

JSON explain

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