SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ff9a3bdcdadc931bbaf5e79e797ac4bc7db09e9392b842c43e32c4692f2ec9a3' 
  AND token = 'rAI/RjPTZJ7QFEmhDBLSQAcmdC43PSkKl95OP5at6Bg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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