SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6d3709600703c60f58c0cea495d47c4387fe1950dfdd9bac2cff4cbfc52f7ba0' 
  AND token = 'abYHpxbo7Brgov2saMfsZxKTaZb8UFhKbansJCycAW0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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