SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd6b5fdda07700874f3293574a0ef9dec990b98226637441a4f7da9b838196321' 
  AND token = 'ylADXxNpJETVZ2R8D8ZyKB2aMuZHaQOVmef3gNYDXOs=' 
  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"
    }
  }
}