SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '17d6761bfd064aecb14b280235f55bb3cc2286ecafc9cc58ac33d21feec861ec' 
  AND token = 'CWqFr5p0FZQnvTd9hcHIW5vpToPX5vUvRhT1ylCfXFg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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