SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '398f9ebe74beedb76bfa6fd527f4134c4e98b836a6016aab03a1252e9a237823' 
  AND token = 'dEKbt0ltqEFXLWhxBumz8MgoA1P6vJUNia33LVWdBKw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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