SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a986c3717ccc5c9225314dd0943a94ae41f0ecb79df56a7fd603feea6ef1211f' 
  AND token = 'ChE/bHUFkSBbS6bSpb/W+8Y7K1Qc/QsRvVheGQ1bI2k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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