SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cbc82d6cc18a60468d0b5d87cee628d41d59238069d7eaa3697eede074c5bde2' 
  AND token = 'GUtRlxB5/TNVb+bMYicbr3taVToC/NXAeydAPvcYCDo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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