SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '78d2bf195821ee180287283eaac8db78d3f0be53e10e141ca1f71e7d3b05b416' 
  AND token = 'v7tt94laMN3Y9TQhODWDMX2grSPFcCV3vQnAYGRgZik=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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