SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2a8aef6520f475782f007283e995e8e6d0bf8fff776b7c5fe3ea14a0f6f283f1' 
  AND token = 'l/hUM+mti7dqfLcbryKMvhQoDuLsJQzPIugC5Abm3vI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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