SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e58ffecb40f27d141b0cc982ab165733864d926f4325471439e2e40c06f5347a' 
  AND token = '1U2i/xPSdWt1FxMUfm0SMsC7o5ybWh4eOaP2MBRbFwo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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