SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4c4063314426cb5b4c9016f2b2b7788cf50485959f98a835f94c1d3f82ae287d' 
  AND token = 'm39u5h/xCPSQrQmMMm5VVwmOInTMesyqwY/UHUBZntE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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