SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '24842f3e92972247a712388db761c553dc2ec48ff3f7267600da5fdd29b6fa5a' 
  AND token = 'cw7hBRtp0avEKmVuE/FsxKhWDsMG6jghX6MXKaRQcwc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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