SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c17ff11c521d1eed71c7c8070958f2a985a21bfa1932d0ce9ce67ba902dec321' 
  AND token = '17Y1h+TEI7xNCIEnWrIiJtQQUykwcOUwtQJWgTt9ywk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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