SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '52bcc6134c5e23c6b29c1d9d203c74b16df7c5f8c976a4929370765f351132bd' 
  AND token = '9hljVccbevPXLeRGiOKS3/Y4twzO9soHKRg/qpFUTuY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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