SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6dfda2b902346f3d936916640a628eea91dea69f0996a66d0e521f5086b9b1f0' 
  AND token = 'IHYmoNtmRum3OR+4Fu8NnJzdAfS+TOWaP2kAzwZsElg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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