SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c0fee51a4897a29fff99661a1f7ed433f399635558e549405a662ac79cdd5b4a' 
  AND token = 'whZw4Bv3Ym221Z0VGSRs92PWkgSvls6BRtqIUlQFFSc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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