SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ab4de1c4dd39ae2c9afe275cf345f6b0c356a922be4c2ebea7425b90197deb15' 
  AND token = 'I8DDY1kNwBGQS7qXXMpW0OuJZYagPoNnjlOFp+rvWK0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00010

JSON explain

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