SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e07bdb6d34a59cec3449601cb96ce251c0e9fc345511a874508faff1382c6f14' 
  AND token = 'SROsfyRIy41YnLSDRkcsI4lqt+j5SBdRbcl/E4UepTw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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