SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1d0649dbc018ede528240737d20f710050055d43835a87b3292497b74a904ef3' 
  AND token = 'A56DrfuGw8Bx+6ecjbw9qJpyDGgkm4Y/pYOZ1fEmGq4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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