SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '30c99f42af2fa4d3ef20d12967ed27f1bba8a4fa95e4aabe83c8a6d60b97f831' 
  AND token = 'er7Gs/UsLGePnP23inSjPtd6e/g7kth9SYCuuF7GMWw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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