SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '15742988f63d1099fec8083291fa44868cf70fa0d30699561a0c5c4005ba13ec' 
  AND token = '/Kjo2+fCoyMbZqsmPFYz94SK3Gzkjn2Tt2AkYZnXWxI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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