SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9a59145a2d0b290c38366c86a1a501c44bd5da31683c4d88878eedd231e6f22a' 
  AND token = 'cUxVK8olOlbJoHdC9WypC2zc/qp3vIMat9HXGv2yB1A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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