SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cd812944f0c222c935d557909e1ee141c9708592c482845383093409c65bbbc9' 
  AND token = 'HzSEDdgdWb20yTAYci5vvgv9gOQC/XJWoQJBFiAaMM4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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