SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a9c63ca3f621ebdad6fefef99ecb32b14995bdd07c8b17d6d85d4837af35607a' 
  AND token = 'JkgtwSkDDUzqFkl42Pc+83CY+Y7F6NKrNUiT1qgMP60=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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