SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd401957bfc345a0b92c1e0b416d38aa689642483195d06bc96563ed7c5091337' 
  AND token = 'mls0epNntkS6ukhPJOc5ruyGf1rHmTOG/T9tVMAv/n8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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