SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c9cebf545f0a401233677bfc5c9a4ea2643d3025213a95f0a02a0f531df32798' 
  AND token = 'yPlEB+wGZJuvWblK8aE/1JMRajO/CinctkFAwLBB9Eo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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