SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bc27546588e78f86d29817a86558a78fbe7489101f10b7a870e316200bf5c272' 
  AND token = 'CwFnJkvYQ4mplCKbEBw0TFy/ahfQ3g/gdl+ndMIalqg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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