SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '49cf0d7a595c7d3b70abf46661a5058d68625d94c21c5174083b6d40a6c4c3ba' 
  AND token = 'hQFdB9Q9Yv++/s9dKeqrdvHPdsN2AqNHhD8NFD+QG9Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00057

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}