SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '966ebe93ea79b8c51c43e2aae1a0a49487cfb03be103f573ca01e8aecbe97e9c' 
  AND token = '/WZzqDryC+TUpYPc/XwMdoXSE6WO3arLY1uUle+BYmQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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