SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3fd115f19750bc75c8d7392610677cd1285a5e04c9458411e0b0c791f292138c' 
  AND token = 'JyPLIrPCmMbXYsNvygrmYHjiBjluWOZDdjUMVbuaiMg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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