SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '54ee7bf4b6249182bf7894f18393f1351226c51887822b3c93cf1c4203123f2d' 
  AND token = 'i7xrd1kilvG+o2F0HMCfTu2SCpPEiIx/xgFhX2LtZU0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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