SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd3fab5b6e3bac18b5e6ab5b523d89b6c5feefda1b73ffb621b531c7ee11283be' 
  AND token = 'ycBTX87Qsgm+3yadN2rZmJ+zH0i0Qpbh4NkhBdrTJD8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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