SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b396c89452ee1e1159c18bdf70133d2d1ebbf46337d5a381582926eb7cd45a0e' 
  AND token = 'jQ3XlCpdV0GZ2XvauYYUR/YHDKXDWjRi1ruVkQRnTyE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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