SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '408b5cbafd48cdeb8b8d85c738115a000cca9123b35c2c0a30f8dca1d2b26a2e' 
  AND token = 'O+7S0gnga7V8TW3WeCr9AV/FyzVSKvbLVPA11yq6s2o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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