SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3411dc3fbab866af21201cdadd8044f2c42a4cc4024ad794c3b06d6fc7abd090' 
  AND token = '+/hvcwmNlUTxfj1OlFAex5aT65lqh4XZYes1a1kV+aI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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