SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ec3373ffe27e47926cfb3b2060c436d08055c37cafccf24466b0bcd3b3422e32' 
  AND token = 'CC8V1wjWIOlBSyoEzSmTQGNIRm3qst1a4wGlc3MriFY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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