SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'eb5ed105ccdc44593665da68ae415d0bfdf7b280526355a899a7f6ba40ef8dae' 
  AND token = 'uikI7ZBH0mkeuSWtg+cHed1cmshq/07nOrskjX9fSX4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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