SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1c78655047bd028a6a916c34bf28e095f21677c4d2e87153de73b30e65fbf360' 
  AND token = 's7zbAIAfw7tveneHISwlyfgqx5/8BfsrfhpwxzJHMCA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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