SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a3a7c64c0938d543c7bd23d4bf7098fe59261d7218875c4fe377c959cd9a0cc5' 
  AND token = 'XjBjywhp4NvYPZfirKIh5WHN+O/rrrzSNobjn1h9+9E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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