SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e4f84a2d498c1c153a92cdbff7501398a301aaa9efcc764355281d6d3416d23d' 
  AND token = 'UZBtEVB2lDVwU/iXFBSfyfiL2FFC3gvXLIXmnKHQ5es=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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