SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e1eadb987f9c27cb70d1e1375de2d585cceaf09e0ef7979897f59cfd7b354d17' 
  AND token = 'hJlB0ISjGS/+HOc5tw7KRcPy3plrf/avRW0APmGX+Wk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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