SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '84406d57ec469b00dcfccc71cf7f5c3b19cf03050479329833edbabf4e90aa88' 
  AND token = 'b3vdHYku7ABDE/+CShKF7LXNmWJ8FgpkTNlsm/GjtCA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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