SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c8decbd9d89d3fcaab02941374a1d25a77eb479fcfdb21f1af32646a99913a81' 
  AND token = '6n76CsPPDUkmjMqnwaI0Eq3LcY0p5BEsUdnzOTSC1tI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}