SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e9d25c4d2170bef65e17753534e0ca50cb2cf4baf384ff2475be5b4c1f27ef65' 
  AND token = 'j+/eKV/y9528DDsfiUWPjPoJSUUpCfdSmIDyX5k9eFc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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