SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9f3e60062d881c3e52ef903fe5820a4395987a3578fb0e5e687e16c1a3fdd665' 
  AND token = '8i0N/doV5kQWOwsN/PAtNfjpbuFIDftaqWXzIl+lmt0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}