SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '78f73f461a6fc4d16cd66e6f119c87e84e07852007588dfc44b581bff41d7357' 
  AND token = '6bAsL3yh4O0BsSqRZQskD0rBpxiabYqTtoDERqhGntw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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