SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b8bff335dd0da54c308a3c0a6b111779cd12907cd8e86adfc2d91aa0505405f6' 
  AND token = 'jLiz2DPruWrBPHyFLnYd+Co3gkId6ThX4YmNHcLM+MA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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