SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '38a622a242a7352c5c41f655c9307c291779365c4e53ddcec720d3def0e40ef8' 
  AND token = 'xw3S1WGZYhbndJbQ7y70ryMYGZYsKIKnn4AlbK7BPSU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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