SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7a7eb120fa3ca35c8f451f6d8cb4d2280c4b39f62ad4ef361b35eb35596d8ca8' 
  AND token = 'Lcq27QCXSV5ZIBYcLqmRP7+ilv9eYYw/A6V+SFxjQU0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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