SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e1b5f41227e737ea6ef29ff72e97d392b9cfedf46d1607d97a7b2d86369a767d' 
  AND token = '8Fj+fdRa6/Gyhjf3dhYLg42hq2b2o8DTaRdBOpkVt+c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}