SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7a9ae8c03da085c3c49c9c19ded74c4703cea51af01cca14ebfda43f72e9a221' 
  AND token = 'PhEbYh+Kfupb17d0DWT+bTZfw2QxnLkP0aXeI/oIIFQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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