SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8349ad2d793bb501241548dc4f70eb0148a1e486ea2e6e09b613c1f31470bf8e' 
  AND token = '50LoO+4oL+DCFONx2jSAzWj7P+6tbOwNfCCY60rcD1c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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